首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   99957篇
  免费   6903篇
  国内免费   2453篇
电工技术   3719篇
技术理论   3篇
综合类   3428篇
化学工业   18905篇
金属工艺   4995篇
机械仪表   6183篇
建筑科学   4889篇
矿业工程   1279篇
能源动力   3861篇
轻工业   7455篇
水利工程   1197篇
石油天然气   2817篇
武器工业   312篇
无线电   13725篇
一般工业技术   16715篇
冶金工业   6397篇
原子能技术   1291篇
自动化技术   12142篇
  2024年   290篇
  2023年   1478篇
  2022年   2382篇
  2021年   3537篇
  2020年   2555篇
  2019年   2535篇
  2018年   2904篇
  2017年   3009篇
  2016年   3323篇
  2015年   3221篇
  2014年   4563篇
  2013年   6027篇
  2012年   6366篇
  2011年   7332篇
  2010年   5704篇
  2009年   5774篇
  2008年   5529篇
  2007年   4814篇
  2006年   4715篇
  2005年   4059篇
  2004年   3284篇
  2003年   3218篇
  2002年   3213篇
  2001年   2700篇
  2000年   2200篇
  1999年   2145篇
  1998年   2522篇
  1997年   1822篇
  1996年   1600篇
  1995年   1194篇
  1994年   933篇
  1993年   754篇
  1992年   606篇
  1991年   487篇
  1990年   419篇
  1989年   370篇
  1988年   342篇
  1987年   254篇
  1986年   197篇
  1985年   156篇
  1984年   137篇
  1983年   91篇
  1982年   78篇
  1981年   59篇
  1980年   50篇
  1979年   55篇
  1978年   36篇
  1977年   43篇
  1976年   73篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 9–11, August, 1993.  相似文献   
64.
The plug loading effect occurring during the etchback of tungsten was investigated in a magnetically enhanced reactive ion etcher using SF 6/Ar mixtures. It was found that while the plug loading effect is independent of varying SF6/Ar flow rate ratio and magnetic field intensity, it is reduced under the condition of high selectivity of tungsten relative to TiN which was achieved at high chamber pressure and low RF power. It is proposed that when TiN is used as a glue layer, the W etch rate enhancement in the plug is mainly controlled by a local loading effect. Under the optimized etchback conditions the plug loss was successfully controlled without the tungsten residue left on severe topology  相似文献   
65.
The effects of the plasma etching process induced gate oxide damages on device's low frequency noise behavior are investigated on MOSFET's fabricated with different field plate perimeter to gate area ratio antennas. Abnormal 1/f noise spectrum with a shoulder centered in the frequency range of 100 and to 1 kHz was frequently observed in small geometry devices, and it is attributable to a nonuniform distribution of oxide traps induced by plasma etching process  相似文献   
66.
Phase-change read-and-write memory (PRAM) is a promising memory that can solve the problems of conventional memory—scalability, read/write speed, and reliability. We will review the opportunities and technical challenges of PRAM. The most important challenge of PRAM is the reduction of the writing current. Various approaches to reduce the writing current will be reviewed and the prospects of PRAM are discussed.  相似文献   
67.
We define the complete joint weight enumerator in genus g for codes over /spl Zopf//sub 2k/ and use it to study self-dual codes and their shadows. These weight enumerators are related to the theta series of the associated lattices and Siegel and Jacobi forms are formed from these series.  相似文献   
68.
This newsletter provides information on past and upcoming events related to the IEEE Computer Society's Test Technology Technical Council and the test community.  相似文献   
69.
70.
The secondary effluent from municipal plants in Korea generally represents higher BOD with lower SS. Therefore, more soluble forms of organics and NH4-N need to be removed to improve its effluent for reuse. In this study reuse possibility of secondary effluent and CSO (combined sewer overflow) using BAF (biological aerated filter) was evaluated. The tertiary application with 1.2 h EBCT, SS, BOD and COD showed stable concentrations less than 1.3, 1.3 and 6.2 mg/L, respectively. Nitrogen could be nitrified even at 7 degrees suggesting BAF can be used for a water reuse method as well as an effective add-on facility in cold regions. However, BAF was not stable with CSO application at increased flow rates suggesting CSO must be equalised prior to application. Disinfection was necessary even during normal weather conditions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号